Gardeners have been waging a war against The Slug for centuries. Now it seems the pest could have met its match - a mathematical equation.

A group of mathematicians are devising a formula that will predict the movements of slugs and whether their numbers will rise or fall. Armed with this information, gardeners can deploy their traditional methods of slug control, such as pellets or broken eggshells, more effectively.

"We are hoping to create a theoretical model that will be of practical use to people trying to control slugs," Said Dr David Schley, one of two leading
mathematicians at Surrey University.

His colleague Dr Martin Bees added: "Data gathered so far indicates that there is a large fluctuation in the number of slugs throughout the year. It appears the population may also travel in waves around a field or garden."

"We are using a set of mathematical tools to detect patterns and recurring trends in a mass of information," Said Dr Schley.

"We hope to come up with a model which people can use to predict where and when sizeable populations of slugs will appear. They can then be tackled in an effective and environmentally friendly manner."

Dr Schley said some preventative methods merely curb the problem until the arrival of the next wave of slugs. "Pellets are very unreliable, they blast the ground and kill things such as predatory beetles, as well as the slugs and snails," he added.

"Then about three weeks later the next batch of slugs comes along and have a clear run at everything because there are no beetles left to prevent them"

Slugs cost farmers up to £11 million a year, while gardeners are only too familiar with the damage they do to seedlings, flowers and vegetables.

A spokesman for the British Agro-Chemicals Association said "Slugs are the most voracious pests we have to deal with."